Peterson bad channel...

[Abraham]

I had a channel which didn't work eventually... now it appears to be definitely gone. I'll check the fuses but I don't think this is a fuse problem as long as this would eventually come back to work like it did before. I have isolated the problem to the main amp. I made sure pre-amp, cable & two power amps are OK.

You know when you plug phones in, the speakers still make sound, don't you? The weird thing is, whenever I plug those, the missing channel is back, not just on the headphones but the speakers also. Any ideas?

[bumpyrhode]

If I understand correctly, the missing channel comes back and there are no issues when
you plug in the headphones.

Common sense tells me that the circuit for that channel is being completed when you plug
the headphones in. Seems the problem is in the wiring between the 4-pin on the power
supply and the headphone jack. Could be a solder joint or dirt/oxidation on the accessory
jacks.

Remove the headphones and plug a short 1/4" cable (like you would use for effects pedals)
in the in/out accessory jack on the amp panel. If the sound comes back that typically indicates
dirty jacks.

[Abraham]

I will put it back toghether just to check out your theory but... as long as line outs are not supposed to mute speakers It doenst make much sense to me anyway... thanks for your answer and Ill post my results later.

thank you!

[Abraham]

well, it worked! thank you bumpy!

I don't know whether this issue will eventually show up again or not but It seems to be fixed now, within the next few days we'll see...

thank you thank you thank you!!!

[Abraham]

The problem is a bad connection on the headphone jack. Whenever a channel stops working I just plug/unplug something several times and then it comes back (the world famous "bumpy method"). Maybe its just dirt or a solder joint who knows, anyway its the jack wich fails and I'll look into fixing/replacing it. It even needs some twisting for both channels to be heard on headphones. I didn't know it because I never used them before.

Also, pluging headphones doesn't mute the speakers but just turns down the output. Is this normal behavior or there's something wrong??

Thank you.

[AFeastOfFriends]

I don't have speakers in, but I can tell you there is no effect on output of the external amp outputs when there are headphones in.